Note: Descriptions are shown in the official language in which they were submitted.
CA 02908972 2015-10-05
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COATED CONDUCTOR WITH VOLTAGE-STABILIZED INNER LAYER
REFERENCE TO RELATED APPLICATIONS
The present application claims the benefit of U.S. Provisional Application No.
61/813.320, filed on April 18, 2013.
BACKGROUND
A typical power cable includes one or more conductors in a cable core
surrounded
by one or more layers of polymeric material. Medium-voltage (6 to 36 kV), high-
voltage
(greater than 36 kV), and extra-high-voltage (greater than 220 kV) cables
typically include a core
surrounded by an inner semiconducting layer, followed by an insulating layer,
and then an outer
semiconducting layer, and an outermost layer (or sheath).
The load-carrying capacity of a cable system is limited, in part, by the heat
transfer away from the conductor. Polyolefins, such as polyethylene, are
frequently utilized in
the insulating layer and/or in the semiconducting layer. Polyethylene has a
low dielectric
permittivity and a relatively high electrical breakdown strength.
Known are voltage-stabilizing agents for polyolefin compositions that increase
electrical breakdown strength of insulating layers in power cable.
Conventional voltage-
stabilizing agents (such as the family of polycyclic aromatics, e.g. acenes),
however, have poor
compatibility with polyolefins. The art recognizes the continuous need for
voltage-stabilizing
agents compatible with polyolefins for (i) increased electrical breakdown
strength of cable
insulation material, (ii) increased reliability with existing cable designs
and/or (iii) provision of
high-stress designs that are able to deliver increased amounts of energy.
SUMMARY
One embodiment is a coated conductor comprising:
a conductor;
an outermost opaque layer;
an inner layer located between the conductor and the outermost layer, the
inner
layer comprising a polymeric composition, which comprises:
a polyolefin; and
a triazine selected from the group consisting of compounds having one of
the structures (I), (II), or (III), and combinations of two or more thereof:
1
81792145
(I)
OH
00 H
n=12.13
. OH
N
I
N''''''
0
(II)
0y0
H OH
(III)
=-=,, ikr i ''''''''=,
...d, i õ..
...,....---,,
(III)
Ett
0 T ii
--, . =
1
%... , P1.1 OH
2
Date Recue/Date Received 2020-09-11
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WO 2014/172107 PCT/US2014/032778
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a power cable in accordance with an embodiment
of the present disclosure.
DETAILED DESCRIPTION
The present disclosure provides a polymeric composition. The polymeric
composition includes (i) a polymeric component, (ii) a voltage-stabilizing
agent, and (iii)
optionally other additives. The present disclosure further provides coated
conductors comprising
such polymeric compositions.
Polymeric Component
The polymeric component may include thermoplastics and/or thermoset material
(such as silicone rubber). The polymeric component may be crosslinked or may
be non-
crosslinked.
Nonlimiting examples of suitable thermoplastics include, polyurethanes,
polyolefins, polyacetals, polycarbonates, vinyl polymers, polyamides,
polyimides, acrylics,
polystyrenes, polysulfones, polyetherketones, cellulosics, polyesters,
polyethers, fluoropolymers,
and copolymers thereof such as olefin-vinyl copolymers, olefin-allyl
copolymers and copolymers
of polyethers and polyamides. Examples of vinyl polymers include polyvinyl
chloride, polyvinyl
acetate. vinyl chloride/vinyl acetate copolymers, polyvinyl alcohol and
polyvinyl acetal.
When it is desired to use a crosslinked polymeric component, crosslinking can
be
accomplished by one or more of the following nonlimiting procedures: free
radical crosslinking
(e.g., peroxide cross-linking); radiation cross-linking (e.g., electron
accelerators, gamma-rays,
high energy radiation, such as X-rays, microwaves, etc.); thermal
crosslinking, and/or moisture
cure crosslinking (e.g., silane-graft).
In an embodiment, the polymeric component is a polyolefin. Nonlimiting
examples of suitable polyolefins are homopolymers and copolymers containing
one or more C2-
Cm a-olefins. For purposes of this disclosure, ethylene is considered an a-
olefin. Nonlimiting
examples of suitable a-olefins include ethylene, propylene, isobutylene, 1-
butene, 1-pentene, 1-
hexene, 4-methyl-1 -pentene, and 1-octene. Nonlimiting examples of suitable
polyolefins include
ethylene-based polymer, propylene-based polymer, and combinations thereof. An
"ethylene-
based polymer", or "polyethylene" and like terms is a polymer containing at
least 50 mole
percent (mol%) units derived from ethylene. A "propylene-based polymer," or
"polypropylene"
and like terms is a polymer containing at least 50 mole percent units derived
from propylene.
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In an embodiment, the polymeric component is an ethylene-based polymer. The
ethylene-based polymer may be ethylene homopolymer or an ethylene/a-olefin
interpolymer.
The a-olefin content is from about 5, or about 10, or about 15, or about 20,
or about 25, wt% to
less than 50, or less than about 45, or less than about 40, or less than about
35, wt% based on the
weight of the interpolymer. The a-olefin content is measured by 13C nuclear
magnetic resonance
(NMR) spectroscopy using the procedure described in Randall (Rev. Macromol.
Chem. Phys.,
C29 (2&3)). Generally, the greater the a-olefin content of the interpolymer,
the lower the
density and the more amorphous the interpolymer, and this can translate into
desirable physical
and chemical properties for the protective insulation layer.
The a-olefin is a C3_20 linear, branched or cyclic a-olefin. Nonlimiting
examples
of suitable of C3_20 cc-olefins include propene. 1-butene, 4-methyl- 1-
pentene, 1-hexene, 1-octene,
1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. The a-
olefins also can
contain a cyclic structure such as cyclohexane or cyclopentane, resulting in
an cc-olefin such as
3-cyclohexyl- 1 -propene (ally] cyclohexane) and vinyl cyclohexane. Although
not a-olefins in
the classical sense of the term, for purposes of this disclosure certain
cyclic olefins, such as
norbornene and related olefins, particularly 5-ethylidene-2-norbornene, are a-
olefins and can be
used in place of some or all of the a-olefins described above. Similarly,
styrene and its related
olefins (for example, a-methylstyrene, etc.) are a-olefins for purposes of
this disclosure.
Nonlimiting examples of suitable ethylene-based polymers include the following
copolymers:
ethylene/propylene, ethylene/butene, ethylene/l-hexene, ethylene/l-octene,
ethylene/styrene,
ethylene-vinyl acetate, ethylene-vinyl propionate, ethylene-vinyl isobutyrate,
ethylene-vinyl
alcohol, ethylenemethyl acrylate, ethylene-ethyl acrylate, ethylene-ethyl
methacrylate,
ethylene/butyl-acrylate copolymers (EBA), ethylene-allyl benzene, ethylene-
ally1 ether, and
ethylene-acrolein; ethylene-propylene (EPR) or ethylene-propylene-diene (EPDM)
rubbers;
natural rubbers; butyl rubbers and the like.
Nonlimiting examples of suitable terpolymers include ethylene/propylene/1-
octene, ethyl ene/propyl ene/butene, ethylene/butene/ I -octene, ethyl
ene/propylene/diene monomer
(EPDM) and ethylene/butene/styrene. The copolymers/interpolymers can be random
or blocky.
The ethylene-based polymer can be high-density polyethylene (HDPE), medium-
density polyethylene (MDPE), low-density polyethylene, (LDPE), linear-low-
density
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polyethylene (LLDPE), and/or very-low-density polyethylene (VLDPE). The
ethylene-based
polymers used in the practice of this disclosure can be used alone or in
combination with one or
more other ethylene-based polymers, e.g., a blend of two or more ethylene-
based polymers that
are "different from one another," which means the ethylene-based polymers are
uncommon by
way of at least one property such as: monomer/comonomer composition and
content, melt index,
melt temperature, degree of branching, catalytic method of preparation, etc.
If the ethylene-
based polymer is a blend of two or more ethylene-based polymers. then the
ethylene-based
polymers can be blended by any in-reactor or post-reactor process. The
reactors can be charged
with the same catalyst but operated at different conditions, e.g., different
reactant concentrations,
temperatures, pressures, etc, or operated at the same conditions but charged
with different
catalysts.
Examples of ethylene-based polymers made with high pressure processes include
(but are not limited to) low-density polyethylene (LDPE), ethylene vinyl
acetate copolymer
(EVA), ethylene ethyl acrylate copolymer (EEA), and ethylene silane acrylate
terpolymers.
Nonlimiting examples of ethylene-based polymers include very-low-density
polyethylene (VLDPE) (e.g., FLEXOMER ethylene/l-hexene polyethylene made by
The Dow
Chemical Company), homogeneously branched, linear ethylene/a-olefin copolymers
(e.g.,
TAFMER by Mitsui Petrochemicals Company Limited and EXACT by Exxon Chemical
Company), homogeneously branched, substantially linear ethylene/cc-olefin
polymers (e.g.,
AFFINITY and ENGAGE polyethylene available from The Dow Chemical Company),
and
ethylene block copolymers (e.g.. INFUSE polyethylene available from The Dow
Chemical
Company). Substantially linear ethylene copolymer is described in USP
5,272,236, 5,278,272
and 5,986,028.
Voltage-Stabilizing Agent
In addition to the polymeric component, the polymeric composition also
includes
a voltage-stabilizing agent (or VSA). A "voltage-stabilizing agent," as used
herein, is a
compound which reduces the damage to a polymeric material when exposed to an
electric field.
It has been considered that a VSA may trap or deactivate electrons to inhibit
electrical treeing in
an insulation material, or otherwise to provide effective screening of hid'
localized fields (near
defects or contaminants) to thereby reduce the energy and/or frequency of
injected electrons
which may impart damage to the polyolefin. Blending the VSA with the polymeric
component
5
81792145
inhibits or otherwise retards treeing. Bounded by no particular theory, it is
believed the VSA
fills and/or surrounds defects in the polymeric component, the defects being
points of tree
initiation. Defects include voids and/or impurities present in the polymeric
component.
The VSA is a triazine selected from one or more of the compounds having the
following structures:
(I)
OH
H
(:).1%:(
=n..12-13
1110 OH
N N
4101
(II)
Q;LOH
OH
N
-N
F."
6
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(III)
Ph
41111 No 0
1 11
0-013 ¨C-0¨ ;C *31f23
0 ,
Ph 011
a) In an embodiment, the polymeric composition contains from about 0.1 wt
%, or
about 0.2 wt % to about 5 wt%, or about 3 wt %, or about 1 wt % of the VSA.
b) In an embodiment, the VSA can be a mixture of two or three different
triazines of
the structures (I) through (III).
c) The foregoing VSAs unexpectedly improve direct current ("DC") breakdown
strength in insulating layers containing the present polymeric compositions.
The improvement in
DC breakdown strength can be seen in the increased DC breakdown strengths
exhibited in
Examples 1-3 described hereafter.
Moreover, the present VSAs exhibit good solubility in the polyolefin matrix
and a
low migration tendency. The present VSAs can be utilized effectively with
other components of
the polymeric composition, in particular to cross-linking agents.
In various embodiments, the polymeric compositions containing one or more of
the above VSAs can have a DC breakdown strength of at least 400 kV/mm, at
least 425 kV/mm,
or at least 450 kV/mm, and up to 700 kV/mm, 650 kV/mm, 600 kV/mm, or 550
kV/mm. DC
breakdown strength is determined according to the procedure provided in the
Test Methods
section, below. In an embodiment, the polymeric composition can have a DC
breakdown
strength in the range of from 467 to 543 kV/mm.
In an embodiment, the polymeric compositions containing one or more of the
above VSAs can have a DC breakdown strength that is at least 5%, at least 10%,
at least 15%. or
at least 20% greater than a comparative polymeric composition having the same
composition but
lacking the VSA. In an embodiment, the polymeric composition containing one or
more of the
above VSAs can have a DC breakdown strength that is in the range of from 10%
to 40%, or from
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13% to 32% greater than a comparative polymeric composition having the same
composition but
lacking the VSA.
Additives
Any of the foregoing polymeric compositions may optionally contain one or more
additives. Nonlimiting examples of suitable additives include antioxidants,
stabilizers,
processing aids, scorch retarders, and/or cross-linking boosters. As
antioxidant, sterically
hindered or semi-hindered phenols, aromatic amines, aliphatic sterically
hindered amines,
organic phosphites, thio compounds, and mixtures thereof, can be mentioned.
Typical cross-
linking boosters may include compounds having a vinyl or an allyl group, e.g.
triallylcyanurate,
triallylisocyanurate, and di-, tri- or tetra-acrylates. As further additives,
flame retardant additives,
acid scavengers, inorganic fillers, water-tree retardants and other voltage
stabilizers can be
mentioned
A "scorch retarder," as used herein is a compound that reduces the formation
of
scorch during extrusion of a polymer composition, at typical extrusion
temperatures used. when
compared to the same polymer composition extruded without said compound.
Besides scorch
retarding properties, the scorch retarder may simultaneously result in further
effects like
boosting, i.e. enhancing cross-linking performance during the cross-linking
step.
The polymeric composition may comprise two or more embodiments disclosed
herein.
Coated Conductor
The present disclosure provides articles containing the present polymeric
compositions. In an embodiment, the article includes a conductor and a coating
on the conductor.
This forms a coated conductor. The conductor may be a single cable or a
plurality of cables
bound together (i.e., a cable core, or a core). The coated conductor may be
flexible, semi-rigid,
or rigid. Nonlimiting examples of suitable coated conductors include flexible
wiring such as
flexible wiring for consumer electronics, a power cable, a power charger wire
for cell phones
and/or computers, computer data cords, power cords, appliance wiring material,
and consumer
electronic accessory cords.
A coating is located on the conductor. The coating may be one or more inner
layers such as an insulating layer and/or a shielding layer and/or a
semiconducting layer. The
coating may also include one or more outer layer(s) (also referred to as a
"jacket" or a "sheath").
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The coating includes any of the present polymer compositions as disclosed
herein. As used
herein, "on" includes direct contact or indirect contact between the coating
(or a layer) and the
conductor. "Direct contact" is a configuration whereby the coating immediately
contacts the
conductor, with no intervening layer(s) and/or no intervening material(s)
located between the
coating and the conductor. "Indirect contact" is a configuration whereby an
intervening layer(s)
and/or an intervening structure(s) or material(s) is/are located between the
conductor and the
coating. The coating may wholly or partially cover or otherwise surround or
encase the
conductor. The coating may be the sole component surrounding the conductor.
Alternatively,
the coating may be one layer of a multilayer structure, jacket, or sheath
encasing the metal
conductor.
In an embodiment, a coated conductor is provided and includes a conductor, an
inner layer and an outermost opaque layer (or sheath). The outermost opaque
layer is the
exposed layer or the layer in contact with the ambient environment. The inner
layer is located
between the conductor and the outermost layer. In other words, the inner layer
is not exposed to
.. the ambient environment, and/or is not exposed to sunlight. The inner layer
includes the
polymeric composition containing polyolefin and the VSA as disclosed above.
The VSA can be
any triazine of structure (I), (II), (III), or a blend of two different
triazines as disclosed herein.
In an embodiment, the inner layer (containing polyolefin and VSA) excludes
layer(s) exposed to sunlight.
In an embodiment, the polymeric composition of the inner layer contains a
polyethylene.
In an embodiment, the polymeric composition of the inner layer contains a
crosslinked polyethylene.
In an embodiment, the coated conductor is a power cable operating at a voltage
greater than 1 kV, or greater than 6 kV to 36 kV (medium voltage), or greater
than 36 kV (high
voltage), or greater than 220 kV (extra high voltage). Figure 1 shows an
insulated power cable
10 (i.e., a coated conductor) which includes a metallic conductor 12, an
internal shielding layer
14, an insulating layer 16, an external shielding layer 18, a metallic screen
20 of wound wires or
conducting bands, and an outennost layer 22 (also known as a sheath). The
outermost layer 22 is
.. opaque.
9
81792145
In an embodiment, the internal shielding layer 14 and/or the insulating layer
16
and/or the external shielding layer 18 are/is composed of a polymeric
composition containing
polyethylene and triazine of the structure (I), (II), and/or (III). In other
words, the inner layer can
be an insulating layer and/or a shielding layer, one or both of which contain
the present
polymeric composition.
The present coated conductor may comprise two or more embodiment disclosed
herein.
DEFINITIONS
All references to the Periodic Table of the Elements herein shall refer to the
Periodic Table of the Elements, published and copyrighted by CRC Press, Inc.,
2003. Also, any
references to a Group or Groups shall be to the Groups or Groups reflected in
this Periodic Table
of the Elements using the IUPAC system for numbering groups. Unless stated to
the contrary,
implicit from the context, or customary in the art, all parts and percents are
based on weight.
Any numerical range recited herein, includes all values from the lower value
to
the upper value, in increments of one unit, provided that there is a
separation of at least 2 units
between any lower value and any higher value. As an example, if it is stated
that the amount of a
component, or a value of a compositional or a physical property, such as, for
example, amount of
a blend component, softening temperature, melt index, etc., is between 1 and
100, it is intended
that all individual values, such as, 1, 2, 3, etc., and all subranges, such
as, 1 to 20, 55 to 70, 197
to 100, etc., are expressly enumerated in this specification. For values which
are less than one,
one unit is considered to be 0.0001, 0.001, 0.01 or 0.1, as appropriate. These
are only examples
of what is specifically intended, and all possible combinations of numerical
values between the
lowest value and the highest value enumerated, are to be considered to be
expressly stated in this
application. In other words, any numerical range recited herein includes any
value or subrange
within the stated range. Numerical ranges have been recited, as discussed
herein, reference melt
index, melt flow rate, and other properties.
Date Recue/Date Received 2020-09-11
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The terms "blend" or "polymer blend," as used herein, is a blend of two or
more
polymers. Such a blend may or may not be miscible (not phase separated at
molecular level).
Such a blend may or may not be phase separated. Such a blend may or may not
contain one or
more domain configurations, as determined from transmission electron
spectroscopy, light
scattering, x-ray scattering, and other methods known in the art.
The "DC breakdown strength" of an insulator is the minimum voltage that causes
a portion of an insulator to become electrically conductive, measured
according to the procedure
provided in the Test Methods section, below.
"Cable" and like terms is at least one wire or optical fiber within a
protective
insulation, jacket or sheath. Typically, a cable is two or more wires or
optical fibers bound
together, typically in a common protective insulation, jacket or sheath. The
individual wires or
fibers inside the jacket may be bare, covered or insulated. Combination cables
may contain both
electrical wires and optical fibers. The cable, etc. can be designed for low,
medium and high
voltage applications. Typical cable designs are illustrated in USP 5,246,783,
6,496,629 and
6,714,707.
"Composition" and like terms mean a mixture or blend of two or more
components. The term "composition." as used herein, includes a mixture of
materials which
comprise the composition, as well as reaction products and decomposition
products formed from
the materials of the composition.
The term "comprising," and derivatives thereof, is not intended to exclude the
presence of any additional component, step or procedure, whether or not the
same is disclosed
herein. In order to avoid any doubt, all compositions claimed herein through
use of the term
"comprising" may include any additional additive, adjuvant, or compound
whether polymeric or
otherwise, unless stated to the contrary. In contrast, the term, "consisting
essentially of'
excludes from the scope of any succeeding recitation any other component, step
or procedure,
excepting those that are not essential to operability. The term "consisting
of' excludes any
component, step or procedure not specifically delineated or listed. The term
"or", unless stated
otherwise, refers to the listed members individually as well as in any
combination.
A "conductor" is an element of elongated shape (wire, cable, fiber) for
transferring energy at any voltage (DC, AC, or transient). The conductor is
typically at least one
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metal wire or at least one metal cable (such as aluminum or copper) but may
include optical
fiber.
"Crosslinked," "cured" and similar terms mean that the polymer, before or
after it
is shaped into an article, was subjected or exposed to a treatment which
induced crosslinking and
has xylene or decalene extractables of less than or equal to 90 weight percent
(i.e., greater than or
equal to 10 weight percent gel content).
An "insulating layer" is a layer having a volume resistivity greater than 101
ohm-
cm, or greater than 1012 ohm-cm.
A -layer," as used herein, is a polymer-based layer surrounding the conductor.
for
example, an electrically insulating layer, a semiconductive layer, a sheath, a
protective layer, a
water blocking layer, or a layer performing combined functions, for example, a
protective layer
charged with a conductive filler.
The term "medium voltage" generally means a voltage of between 6 kV and about
36 kV, whereas "high voltage" means voltages higher than 36 kV, and "extra
high voltage"
generally means voltages greater than 220 kV. The skilled artisan understands
that these general
voltage ranges may be different outside of the United States.
The term "opaque," as used herein, is a material that blocks at least natural
light
(i.e., sunlight). In other words, an opaque material is impenetrable to light
energy having a
wavelength from about 250 nm to about 800 nm.
The term "polymer" is a macromolecular compound prepared by polymerizing
monomers of the same or different type. "Polymer" includes homopolymers,
copolymers,
terpolymers, interpolymers, and so on. The term "interpolymer" is a polymer
prepared by the
polymerization of at least two types of monomers or comonomers. It includes,
but is not limited
to, copolymers (which usually refers to polymers prepared from two different
types of monomers
or comonomers, terpolymers (which usually refers to polymers prepared from
three different
types of monomers or comonomers), tetrapolymers (which usually refers to
polymers prepared
from four different types of monomers or comonomers), and the like.
A "shielding layer" may be semiconductive or resistive. A shielding layer
having
semiconductive properties has a volumetric resistivity value, of less than
1000 n-m, or less than
500 n-m, when measured at 90 C. A shielding layer having resistive properties
has a volumetric
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resistivity value greater than a semiconductive layer. A shielding layer
having resistive
properties typically has a dielectric constant greater than about 10.
TEST METHODS
DC Breakdown Strength Measurement
The DC breakdown strength measurements are performed using an apparatus
utilizing a rounded 0.25" probe and a large flat copper plate. For each test
the voltage is raised at
a rate of 300 V/s until a breakdown is detected. "Breakdown" is defined as the
point where the
voltage read by the power source suddenly drops to below 10% of the set value.
This method is
chosen as opposed to current spike measurements to eliminate false positives
from static
discharge. This DC breakdown test procedure is very similar to ASTM D149 (for
AC tests) with
considerations from ASTM D3755 (for DC tests). The DC breakdown strength is
the voltage at
which the sample failed normalized to thickness. The ASTM method suggests five
measurements per sample for an adequate standard deviation; however, early
tests here revealed
that the standard deviation does not level until approximately ten tests,
while the standard error
continues to drop further. As a compromise between standard error and time,
ten measurements
are made for each sample, and an average value is provided as the DC breakdown
strength of the
material.
EXAMPLES
Sample Preparation
PE resin containing certain amount of additive is first dry blended, and then
the
mixture is melt-blended on a micro 18-mm twin-screw extruder at a speed of
¨200 RPM. The
throughput is 7 lb/h with a melt temperature of about 180-200 C. The extruded
strand is air-
cooled and chopped into pellets.
PE films containing certain amount of additives are fabricated by using a
single
screw extruder. The films are casted at temperature in the range of 170-210 C
along the
extruder. The Die Gap is set as 4 mm and Chill Roll Temperature is 40 C. The
film thickness
is around 1-2 mils.
Examples 1-3 and Comparative Samples A-C
Example 1 is LDPE containing 1 wt% of the following triazine voltage-
stabilizing
agent, which is an 85 wt% solution in 1-methoxy-2-propanol:
13
81792145
OH
00 fi
n =12.13
11110 OH
N
I
N''''''
0
which is available under the brand name TINUVINTm 400 from BASF. The LDPE
employed in
this example is LDPE DXM446 from The Dow Chemical Company, Midland, MI, USA.
Example 2 is LDPE containing 1 wt% of the following triazine voltage-
stabilizing
agent:
OH
.1 OH
...-.'
.....-;*.
which is available under the brand name TINUVINTm 405 from BASF. The LDPE
employed in
this example is the same as described in Example 1.
Example 3 is LDPE containing 0.85 wt% of the same voltage-stabilizing agent
employed in Example 2. The LDPE employed in this example is the same as
described in
Example 1.
Example 4 is LDPE containing 1 wt% of the following triazine voltage-
stabilizing
agent:
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Ph
0 t6le 0
I 11
0¨Cli ¨ C-0¨ (C it H1,7 -Jac)
N
le
Ph OH
which is available under the brand name TINUVINTm 479 from BASF. The LDPE
employed in
this example is the same as described in Example 1.
Comparative Sample A is LDPE with no voltage-stabilizing agent. The LDPE
employed in Comparative Sample A is the same as described in Example 1.
Comparative Sample B is LDPE containing 1 wt% CYASORBTm UV 1164,
having the structure:
Hat: 0 CH3 Ho OCArn
-.
I
N , N
An CH3
"I
CH,
The LDPE employed in Comparative Sample B is the same as described in Example
1.
Comparative Sample C is LDPE containing 1 wt% CHEVIASSORBTm 944, a
hindered amine stabilizer having the structure:
r
_._..---14',./
---4,..?...
: I ------ f -I r-
L )4\
1 T ..
H
N H
i
tett
The LDPE employed in Comparative Sample C is the same as described in Example
1.
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Examples 1-3 and Comparative Samples A-C are analyzed for DC breakdown
strength according to the above-described procedure. Results are provide in
Table 1, below:
Table 1 ¨ Breakdown Strength Analysis
Average DC
% Breakdown
Breakdown
Samples Additive name strength
strength,
improvement
(KY/mm)
Comparative
None 412.381
Sample A
Comparative CYASORB
369.303 -10.4
Sample B UV1164
Comparative CHIMASSORB1m
374.199 -9.3
Sample C 944
Example 1 TINUVINHvi 400 495.295 20.1
Example 2 TINUVINIm 405 467.058 13.3
0.85% TINUVINim
Example 3 405 507 22.9
Example 4 TINUVINnvi 479 542.3 31.5
Breakdown strength results indicate that special/unique triazine type
structures TINUVINTm 400,
405, and 479 provide significant DC voltage stabilization performance compared
with other
triazine structures, such as CYASORBTm UV 1164 and CHIMASSORBTm 944.
It is specifically intended that the present disclosure not be limited to the
embodiments and illustrations contained herein, but include modified forms of
those
embodiments including portions of the embodiments and combinations of elements
of different
embodiments as come within the scope of the following claims.
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